With the proliferation of computers and information networking in recent years, electronic mail (E-mail) for transmitting text information over a network has become widely used. Along with message body, which is text information, files in various formats can be sent as (E-mail) attachments. For example, Internet faxes (hereinafter abbreviated to “IFAX”) which can transmit images as TIFF (Tag Image File Format) files attached to E-mail are widely used.
IFAX is a technology for communications between devices that enables a transmitting device to transform an image scanned through a scanner into the TIFF format and send the TIFF image and enables a receiving device to reproduce and print the image in the TIFF format from the data it has received.
One known example of such technology is RFC 2301, which is an IFAX image standard that specifies tags of resolution information and pixel count information in TIFF image files (see <URL:http:ietf.org/rfc/rfc2301.txt>). Another known technique adds information about sheet size to image data and sends and receives the data by E-mail (see Japanese Patent Laid-Open No. 11-225263).
When resolution or pixel count information is recorded in an image as described in RFC 2301, the size of the image (sheet size) can be obtained from the resolution and pixel count information. When resolution or sheet size information is recorded in an image as described in Japanese Patent Laid-Open No. 11-225263, pixel count information can be obtained from the information.
Images taken with digital cameras typically have pixel count information recorded on them, but not information about resolution or sheet (or image) size. Therefore, when an image taken with a digital camera is to be printed, a sheet size is typically specified by a user through a print application program to provide the sheet size information to cause the image to be printed on a sheet of the specified size.
However, there is a problem that when an image taken with a digital camera and attached to E-mail is to be printed on an IFAX machine, the image cannot properly be printed because the size of a sheet on which the image is to be printed cannot be determined unless resolution information or sheet size information is recorded in the attached image.